Systems and Method for Tire Road Limit Nearness Estimation

Abstract

For one embodiment of the present invention, a computer implemented method of determining tire road limit nearness estimation is described. The computer implemented method includes obtaining sensor signals from a sensor system of a vehicle to monitor driving operations and to determine localization of the vehicle. The method further includes determining lateral force disturbances for front and rear lateral accelerations and a bulk longitudinal force disturbance for the vehicle based on the localization and the sensor signals and determining a tire road limit nearness estimation for the vehicle based on the sensor signals, the lateral force disturbances for front and rear lateral accelerations and the bulk longitudinal force disturbance.

1 . A computer implemented method comprising:
 obtaining sensor signals from a sensor system of a vehicle to monitor driving operations and to determine localization of the vehicle;   determining lateral force disturbances for front and rear lateral accelerations and a bulk longitudinal force disturbance for the vehicle based on the localization and the sensor signals;   determining whether tire force and tire slip signals are detected to indicate a limit friction event for a nonlinear handling region; and   determining a tire road limit nearness estimation for the vehicle based on the tire force and tire slip angle signals, the lateral force disturbances for front and rear lateral accelerations and the bulk longitudinal force disturbance when the tire force and tire slip signals are detected for a nonlinear handling region.   
     
     
         2 . The computer implemented method of  claim 1 , further comprising:
 periodically receiving a priori handling limit estimate for tire road friction from a vehicle capabilities node.   
     
     
         3 . The computer implemented method of  claim 2 , further comprising:
 for no detected observable tire force and tire slip signals, applying the a priori handling limit estimate for tire road friction during a linear handling region.   
     
     
         4 . The computer implemented method of  claim 1 , further comprising:
 receiving a feedback signal from an electronic control unit (ECU) including an anti-lock braking system (ABS) signal, a traction control system (TCS) signal, or an electronic stability control (ESC) to indicate a limit friction event for the nonlinear handling region.   
     
     
         5 . The computer implemented method of  claim 1 , further comprising:
 sending the tire road limit nearness estimation to planning and control systems.   
     
     
         6 . The computer implemented method of  claim 1 , further comprising:
 determining current driving conditions for the vehicle in the nonlinear handling region; and   modifying driving behavior of the vehicle to safely control the vehicle during the limit friction event in the nonlinear handling region with the tire road limit nearness estimation being applied for modifying the driving behavior.   
     
     
         7 . The computer implemented method of  claim 1 , wherein the sensor signals comprise tire force signals, tire slip angle signals, and ranging signals for localization of the vehicle and nearby objects within a certain distance of the vehicle and the sensor system. 
     
     
         8 . A computing system, comprising:
 a memory storing instructions; and   a processor coupled to the memory, the processor is configured to execute instructions of a software program to:   obtain sensor signals from a sensor system of an autonomous vehicle to monitor driving operations and to determine localization of the autonomous vehicle;   determine lateral force disturbances for front and rear lateral accelerations and a bulk longitudinal force disturbance for the autonomous vehicle based on the localization and the sensor signals;   determine whether tire force and tire slip signals are detected to indicate a limit friction event for a nonlinear handling region; and   determine a tire road limit nearness estimation for the vehicle based on the tire force and tire slip angle signals, the lateral force disturbances for front and rear lateral accelerations and the bulk longitudinal force disturbance when the tire force and tire slip signals are detected for a nonlinear handling region.   
     
     
         9 . The computing system of  claim 8 , wherein the processor is configured to execute instructions to:
 periodically receive a priori handling limit estimate for tire road friction from a vehicle capabilities node.   
     
     
         10 . The computing system of  claim 9 , wherein the processor is configured to execute instructions to:
 for no detected observable tire force and tire slip signals, apply the a priori handling limit estimate for tire road friction during a linear handling region.   
     
     
         11 . The computing system of  claim 10 , wherein the processor is configured to execute instructions to:
 receive a feedback signal from an electronic control unit (ECU) including an anti-lock braking system (ABS) signal, a traction control system (TCS) signal, or an electronic stability control (ESC) to indicate a limit friction event for the nonlinear handling region.   
     
     
         12 . (canceled) 
     
     
         13 . The computing system of  claim 8 , wherein the processor is configured to execute instructions to:
 determine current driving conditions for the vehicle in the nonlinear handling region.   
     
     
         14 . The computing system of  claim 13 , wherein the processor is configured to execute instructions to:
 modifying driving behavior of the vehicle to safely control the vehicle during the limit friction event in the nonlinear handling region with the tire road limit nearness estimation being applied for modifying the driving behavior.   
     
     
         15 . (canceled) 
     
     
         16 . (canceled) 
     
     
         17 . (canceled) 
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . A computer implemented method comprising:
 receiving a feedback signal from an electronic control unit (ECU) of an autonomous vehicle (AV);   determining whether tire force and tire slip signals of the AV are detected to indicate a limit friction event for a nonlinear handling region; and   determining real-time handling limit estimation including a tire road limit nearness estimation for the AV based partially on the feedback signal when the tire force and tire slip signals are detected for a nonlinear handling region.   
     
     
         22 . The computer implemented method of  claim 21 , further comprising:
 receiving an expected state of an autonomous vehicle (AV);   determining an actual state and disturbance estimation of the AV based on the expected state of the AV and the feedback signal; and   determining a road grade angle and road bank estimation.   
     
     
         23 . The computer implemented method of  claim 22 , further comprising:
 providing the actual state and the real-time handling limit estimation for tire road friction during the nonlinear handling region to a vehicle capabilities node.   
     
     
         24 . The computer implemented method of  claim 23 , further comprising:
 mapping, with the vehicle capabilities node, the real-time handling limit estimation to constraints for acceleration, velocity, or curvature; and   performing constraint management based on the real-time handling limit estimation.   
     
     
         25 . The computer implemented method of  claim 24 , further comprising:
 providing proactive environmental condition management based on receiving an environmental condition signal from on-vehicle detection sensors.   
     
     
         26 . The computer implemented method of  claim 21 , further comprising:
 modifying model parameters including tire parameters based on the actual state and the real-time handling limit estimation for tire road friction.   
     
     
         27 . The computer implemented method of  claim 21 , wherein the feedback signal includes an anti-lock braking system (ABS) signal, a traction control system (TCS) signal, or an electronic stability control (ESC) to indicate a limit friction event for the nonlinear handling region. 
     
     
         28 - 40 . (canceled)